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2–16 975-0012-01-02 Rev A
Battery Cable Sizing
Proper cable sizing (diameter and length) is critical to the safe and efficient
operation of an inverter system. Larger diameter cables (smaller AWG number)
have less voltage drop and are, therefore, more efficient when transferring power
to and from the batteries. If a cable is undersized (diameter too small), it could
potentially overheat, creating a fire hazard.
Cable length is another important factor. Runs should be kept as short as practical.
Longer cable runs increase resistance, thus lowering the overall efficiency of the
system. This is especially true in lower voltage systems (i.e., 12 Vdc) where,
depending upon the length of the cable run, it may be necessary to oversize the
diameter of the wire, or parallel (double) the cables.
Table 2-3 provides recommended minimum cable sizes for various cable lengths
and inverter amperages. These recommendations may not meet all local or NEC
requirements.
Important:
Only use copper cables. Always use a properly sized cable and length rated
for the amperage of the inverter and batteries.
WARNING: Fire Hazard
Undersized cables can overheat and melt, creating a fire hazard when subjected to heavy
(peak) loads.
Important:
Run the positive and negative battery cables as close to each other as
possible by taping them together. This reduces the effects of inductance and produces a
better waveform thus increasing efficiency. See Xantrex Technical Note 008 on the
Xantrex website for additional information on Battery Cable Inductance.
Table 2-3
Minimum Recommended Battery Cable Size versus Length
Inverter
Model
Typical
Amperage 1 to 3 feet (one-way) 3 to 5 feet (one-way) 5 to 10 feet (one-way)
DR1512 150 A
#2/0 AWG (67.4 mm
2
) #2/0 AWG (67.4 mm
2
) #4/0 AWG (107 mm
2
)
DR2412 240 A
#4/0 AWG (107 mm
2
) #2/0 AWG (67.4 mm
2
) #2/0 AWG (67.4 mm
2
)
DR1524 75 A
#2/0 AWG (67.4 mm
2
) #2/0 AWG (67.4 mm
2
) #2/0 AWG (67.4 mm
2
)
DR2424 120 A
#2/0 AWG (67.4 mm
2
) #4/0 AWG (107 mm
2
) #4/0 AWG (107 mm
2
)
DR3624 180 A
#4/0 AWG (107 mm
2
) #4/0 AWG (107 mm
2
) #4/0 AWG (107 mm
2
)
Important:
If the system includes a large battery bank or large DC source (such as a
micro-hydroelectric plant or wind generator), increasing the size of the cables and
disconnects will greatly reduce the number of nuisance outages associated with breaker
tripping and open fuses.